The build up to the Second Genome Editing Summit in Hong Kong was a fairly routine affair. There was little to draw attention to the impending gathering of people from across the world to discuss the important and technically complex topic of altering the human genome. But the day before the summit began, there was a moment of drama as it was announced the Chinese Academy of Sciences, one of the co-organisers of the first summit in Washington two years earlier, had dropped out months before. The news created ripples and was sufficient to pique the interest of a few journalists. It seemed like this might be one of the bigger stories of the summit. Within hours the story was lost in history-changing news that a Chinese scientist, He Jiankui, had edited the genomes of embryos and implanted them, resulting in the birth of twins. Global shock and condemnation were immediate.

Scientists and clinicians have previously treated a small number of patients using genome editing, but in these cases the changes were made in cells that would not be passed on to the next generation, and only in one type of tissue, usually blood or lungs. In some of the cases, the cells containing the changes died out as the person’s own, unaltered cells took back over. What He Jiankui had done was completely different. By editing embryos, the changes made will be passed on to the next generation. Every cell in these babies’ bodies will contain the changed genome. It was also illegal in many countries including the UK and the EU.

As news of the edited babies spread, more details emerged, but so did conflicting accounts of what had happened. It quickly became clear that He had chosen to edit healthy embryos that were part of an otherwise routine IVF treatment. He had altered a gene known as CCR5.

HIV immunity?

Naturally occurring variations in CCR5 are known to make individuals more resistant to HIV infection, but the full function of CCR5 is not known. There is also evidence that the same variation that makes an individual immune to HIV makes them more susceptible to West Niles Virus. These are complex systems and because He had edited it in the embryo, every tissue carries the change in CCR5. If the CCR5 gene has a function outside the immune system, those body functions will be affected too.

Hot on the heels of the news that He had edited healthy embryos came news that the editing had “worked” in one twin, but had only partially worked in the other twin. This second twin had one altered copy of the CCR5 gene and one original copy. He had chosen to implant this embryo anyway, despite the fact that partial editing means the baby probably won’t have immunity against HIV infection – He’s justification for the editing in the first place.

Next followed the hospital He worked at denying all knowledge of the project and denouncing the work. Questions quickly followed about the oversight and ethics approvals for the research, the answers to which seemed only to create more questions. None of the work had been peer reviewed and little data was available to verify He’s claims.

The Summit

Meanwhile, the Summit, which hadn’t begun when the news story broke, was now opening with a bang. More importantly, He was one of the delegates. As experts on different aspects of genome editing were taking to the stage, the news of He’s work was making headlines around the world. Journalists were descending on the venue, and organisations and individuals were putting out statements largely denouncing the work.

In a frenzy of media attention, less than 48 hours after his announcement, He joined a panel discussion with scientific heavyweights including Kathy Niakan, the first scientist in the UK to get permission to edit embryos for research purposes. The panel discussion had always been part of the agenda, but now had an entirely new significance.

The fact that He joined the group and stood up on the stage to talk about his work is worth reflecting on. In the aftermath of his news, which he suggested had been unintentionally leaked, sensationalist headlines and statements condemned not only the science but also the scientist, sometimes in the most heated of terms.

Most scientists are unused to media attention and many will actively shun it, but He stood up. He presented his work and answered questions from the panel, the audience and the assembled press. His answers were not particularly reassuring; his participants were recruited in a manner unlikely to be considered ethical in many countries. His reasoning for choosing CCR5 was flimsy and his view that his work was ethical and in compliance with good practice was in stark contrast to the views of much of the world and the audience directly in front of him. But at the same time, He was there.

There is probably little to defend in what He did. The line between pioneer and villain is vanishingly faint at the best of times. Whether someone is deemed a visionary or a cowboy has more to do with popular opinion and the outcome than their motivations or the precautions they took. He has leapt ahead with a technology we do not fully understand and the consequences for the twins could be severe indeed. The justification of providing HIV immunity, when HIV transmission to embryos is preventable and the disease has management strategies, is weak. Editing healthy embryos seems indefensible. But, the worst thing we could do now is drive scientists like He underground.

Genome editing – when, not if

Scientists, regulators and policy makers have known for a long time that it was a case of when, not if, an embryo would be edited. We should use this moment to learn what we can, we should ensure these babies do not disappear, left to an uncertain fate. It may be unpalatable to many, but it is imperative that we engage with He. Not least to know what was done and how he got so far unchecked, so we can all learn lessons from this incident. He did not operate in a vacuum, and there are a lot of questions that need to be answered, many of which will start with his account.

Scientists are often driven by a combination of wanting to make a difference and wanting to be first. Keeping scientists in the fold is one of the most important ways scientists can regulate themselves, particularly where legislation doesn’t. He has said his desire was to tackle a health crisis in China – to make a difference with a challenging issue. It is probably easy to dismiss He as an unregulated outlier, but the drivers of stigma relating to a health status, desperation for a family, and lack of access to health care are universal problems. If we fail to tackle these global issues, genome editing of embryos may be an attractive option to the desperate and the vulnerable.

The future

The organising committee of the Second Genome Editing Summit has released a statement, reiterating their view that genome editing in a way that is inherited should not be allowed at this time. They also reiterated the need for countries to engage in public discussion and debate on genome editing. He has shown that genome editing of embryos is a real consideration, but he has also shown us that the global science community is together in its opposition to editing of embryos at this time. Although undoubtedly unintentional, He has also offered us a meaningful starting point for that public conversation – which might ultimately be the most important thing that comes from this.